1. Field of the Invention
This invention relates to an image forming device capable of reducing a force of rolling up both ends of a blade-like member, and preventing lowering of cleaning performance due to the rolling up of the blade-like member.
2. Description of the Background Art
An image forming device of an electrophotographic system, for example, a copier, a facsimile device and a printer, equipped with an endless belt-like rotatable transferring/carrying belt, and a cleaning means for cleaning the transferring/carrying belt, besides a charging means, an exposing means and a developing means, is known.
In an image forming operation in such an image forming device, first, a latent image carrier is uniformly charged by the charging means, then an electrostatic latent image is formed on the latent image carrier by exposing the image by the exposing means. The electrostatic latent image is developed by the developing means to form a developed image, and the developed image on the latent image carrier is transferred to a recording medium carried by the transferring/carrying belt by a transferring/carrying means using the transferring/carrying belt in a transferring region wherein the latent image carrier faces the transferring/carrying belt. The recording medium having the developed image transferred thereon is carried to a fixing means to fix the developed image on the recording medium.
In such an image forming device, surplus toner seldom deposits on the transferring/carrying belt. The toner remaining on the latent image carrier, however, is sometimes transferred to the transferring/carrying belt, when the size of the recording medium does not coincide with the region of the toner image on the latent image carrier, or when a carrying jam of the recording medium occurs.
When the toner is deposited on the transferring/carrying belt, the toner on the transferring/carrying belt must be removed by cleaning the surface of the belt.
A cleaning device for removing the toner on the transferring/carrying belt by bringing the blade-like member in contact with the belt is generally used as the cleaning device for cleaning the transferring/carrying belt. The higher is the contact pressure of the blade-like member to the transferring/carrying belt, the higher becomes the cleaning performance to the belt.
A cleaning device for removing the toner on the transferring/carrying belt by bringing the blade-like member into contact with the belt from the counter direction, is disclosed, for example, in H2-034882 of the Japanese Patent Laid-Open Publications. In this cleaning device, as the blade-like member is brought into contact with the transferring/carrying belt from the counter direction, the contact pressure between the blade-like member and the belt becomes large. This has merit in that the cleaning performance to the belt is superior to that of a cleaning device where the blade-like member is brought into contact from a trailing direction.
When the blade-like member is continuously brought into contact with the endlessly moving belt, however, the part of the blade-like member in contact with the belt becomes soft by heat to be possibly rolled up. At the contact part of the blade-like member, in particular, both ends in the extending direction have a high degree of freedom of deformation to easily roll up compared to the central part of the contact part. Rolling up of both ends of the contact part triggers the rolling up of the central part of the blade-like member. The rolling up of the blade-like member thus causes various failures such as, lowering of the cleaning performance to contaminate the rear face of the recording medium, or increase of the load of driving the belt so as to break driving system.
Various failures as mentioned above due to the rolling up of the blade-like member can occur in cleaning belt-like members besides the transferring/carrying belt, and not limited to the case of cleaning the transferring/carrying belt. For example, a failure can also occur in the case of cleaning by bringing the blade-like member into contact with the belt-like member such as, a photoreceptor belt and an intermediate transferring/carrying belt used in the image forming device.
Technologies relating to the present invention are also disclosed in, e.g., Japan Patent Laid-Open Publication No. H08-106218, No. 2003-202701, and No. 2003-228202.